Suture anchors are widely used in surgery, particularly for attaching sutures to bones in orthopedic surgical procedures. The suture anchor connects a portion of a suture to a bone, while the remainder of the suture (typically, two segments extending from the suture anchor) is used for various applications, e.g., for securing loosened connective tissue, such as ligament, to the bone. The suture anchor is typically driven into a hole made in the bone, e.g., into a pre-drilled hole. Suture anchors are particularly useful for firmly attaching sutures to bones during and after orthopedic surgery.
Suture anchors and tools for installing suture anchors are described in U.S. Pat. Nos. 5,207,679, 5,411,523 and 5,217,486, and in PCT publication WO 96/28100.
U.S. Pat. No. 5,411,523 describes a suture anchor and installation tool combination. The suture is threaded through a ring attached to a removable link member which is connected to an installation end of the installation tool. The threaded suture is folded into two free-ended segments which are guided together through a single bore formed in the installation tool. By applying a driving force to the installation tool, the suture anchor is driven into a pre-drilled hole in the bone together with a portion of the suture.
PCT publication WO 96/28100 also describes a suture anchor installation tool, wherein the suture is attached to the suture anchor and two free-ended segments of the suture are guided together through the installation tool. The suture anchor is driven into the bone by a force which is transmitted thereto by the installation tool.
Likewise, both U.S. Pat. Nos. 5,207,679 and 5,217,486 describe an installation tool for a suture anchor. In the devices described in these patents, the suture is threaded through a loop which is attached to the suture anchor and the installation tool drives the suture anchor into a pre-drilled hole, but the free ended segments of the suture are not guided through the installation tool.
Each of the prior art devices described above is susceptible to the effect of lateral forces which may act on the suture anchor and/or on the installation tool during installation. In response to such lateral forces, the installation tool may skew with respect to the suture anchor and/or the suture anchor may skew in the pre-drilled hole. Consequently, the suture anchor and/or the installation tool may be damaged and the suture anchor may be improperly installed in the bone.
Further, in prior art devices, a certain degree of freedom between the suture anchor and the installation tool may result in lateral movement of the suture anchor upon installation. Such lateral movement makes it difficult to align the suture anchor with respect to the pre-drilled hole. Thus, installation of a suture anchor is generally difficult and requires very high precision. Additionally, there is often insufficient space for maneuvering the installation tool at the installation site to compensate for lateral movement of the suture anchor.